In general, a styrene-based copolymer, for example, a styrene-acrylonitrile copolymer, is being widely used in various industrial fields including office automation (OA) equipment, such as a computer, a printer, and a copy machine, home appliances, such as a television and an audio, electrical and electronic parts, automotive parts, and miscellaneous goods due to excellent formability, stiffness, and electrical properties. In particular, a heat-resistant styrene-based copolymer, which withstands a high external temperature by increasing heat resistance, is being used for special purposes, for example, housings for home appliances and automobile interior materials.
Excellent surface properties, such as transparency, are essentially required for a resin used as an exterior material such as a material for food containers, but, since a styrene-based copolymer prepared by a conventional preparation method contains a large amount of an oligomer component, fume and gas may be generated during processing of the styrene-based copolymer. Thus, processability may not only be low, but also surface properties of a processed product prepared may be reduced and heat resistance and weather resistance may be reduced. Thus, research to develop a styrene-based copolymer having a low oligomer content while maintaining original characteristics of a styrene-based copolymer has been conducted.
However, a styrene-based copolymer having excellent impact resistance or excellent impact resistance and heat resistance is being developed through much research, but development of a styrene-based copolymer, which may have excellent surface properties due to a low oligomer content while having excellent impact resistance and heat resistance, is insignificant.
Thus, in order to further increase utilization of a styrene-based copolymer, there is a need to develop a styrene-based copolymer having improved surface properties.